This invention relates to a waterproof plug for a waterproof connector, and more particularly to a waterproof plug of a waterproof connector which forms a waterproof seal between a cavity, formed in a housing of the waterproof connector, and a wire which is inserted in the cavity and connected to a terminal.
A waterproof plug for a waterproof connector is disclosed in JP-B-64-35675U. As shown in FIG. 5, this waterproof plug 60 includes a larger-diameter portion 61 of a generally cylindrical shape, and a smaller-diameter portion 65 of a generally cylindrical shape. Outer peripheral ribs 62 are formed on an outer peripheral surface of the larger-diameter portion 61 while inner peripheral ribs 63 are formed on an inner peripheral surface of the larger-diameter portion 61.
To mount this waterproof plug 60 on the waterproof connector, first, a wire 67 (shown in FIG. 6) is inserted into the waterproof plug 60 from the larger-diameter portion 61 toward the smaller-diameter portion 65. At this time, the inner peripheral ribs 63 on the larger-diameter portion 61 are press-contacted with an outer peripheral surface of the wire 67.
Then, the smaller-diameter portion 65, serving as a clamping portion, is compressively clamped by an insulation barrel 69 of a terminal 68, thereby connecting the waterproof plug 60 and the wire 67 to the terminal 68.
In this condition, the terminal 68 is inserted into a cavity 72 in a housing 70 in a direction of an arrow, and subsequently the waterproof plug 60 is press-fitted into the cavity 72. As a result, the outer peripheral ribs 62 on the larger-diameter portion 61 are press-contacted with an inner surface of the cavity 72 to form a hermetic seal, that is, a waterproof seal, therebetween.
However, the smaller-diameter portion 65 (serving as the clamping portion) of the waterproof plug 60, formed into a small size, has a reduced thickness, and therefore when the smaller-diameter portion 65 is compressively clamped by the insulation barrel 69 of the terminal 68, a distal end portion 66 of the smaller-diameter portion 65 is raised as shown in FIG. 6. The raised distal end portion 66 of the smaller-diameter portion 65 interferes with the inner peripheral surface of the cavity 72, and is turned up.
Among the waterproof connectors disclosed in JP-B-64-35675U, there is the one shown in FIG. 7. In this waterproof connector 80, an annular projection 81 is formed on an inner peripheral surface of a smaller-diameter portion 65 at a distal end thereof, so that the distal end portion 82 of the smaller-diameter portion 65 (serving as a clamping portion) has an increased thickness t1.
Therefore, when the smaller-diameter portion 65 is compressively clamped by the insulation barrel 69 of the terminal 68, the distal end portion 82 of the smaller-diameter portion 65 is prevented from being raised.
In this waterproof plug 80, however, the distal end portion 82 of the smaller-diameter portion 65 has the increased thickness t1, and therefore when the smaller-diameter portion 65 is compressively clamped by the insulation barrel 69 of the terminal 68, the distal end portion 82, having the thickness t1, is bulged. As a result, the bulged distal end portion 82 interferes with the inner peripheral surface of the cavity 72 (see FIG. 6), and is turned up.